Therapeutic cloning is defined as the process of embryonic cloning to treat specific conditions and diseases. Within this process, human embryonic cells are utilized to create genetically identical cells for regenerative medicine. This process allows for the replacement of regenerative tissues and organs, provided by their embryonic cells, for transplantation. Therapeutic cloning, and its implications, go against certain beliefs. Science has clashed with religion since for centuries, and the ethics of the therapeutic cloning process is one issue that is disagreed upon by many.
http://cmgm.stanford.edu/biochem118/images/Stem%20Cell%20Slides/10.%20Therapeutic%20Cloning.jpg
What are stem cells?
Stem Cells, also termed as pluripotent stem cells, are the cells capable of developing into any cell type of the body during early stages of development. Also, in many tissues, these cells provide an essential cellular repair system to damaged tissue cells in need of repair; dividing without boundaries to repair or replenish other cells as long as the person or animal is living. When these stem cells start dividing, the new cells are capable to retain itself as a stem cell or to transform into any other cell with a more specialized function, like as muscle cells, brain cells, or blood cells.
Stem cells differ from any type of cell by two major characteristics. They are first unspecialized cells capable into renewing themselves after long periods of inactivity. Second, like mentioned before, under certain circumstances these cells can be induced into the transformation of specific tissue or organ cells with special functions. In some organs, such as bone marrow, stem cells divide to repair or replace damaged or worn out tissues. In other cases, like for example the heart, stem cells only divide under special conditions.
The importance of stem cells, for living organisms, is the ability, from the inner cells of the blastocyst, to give rise to the entire body of organisms and of the many specialized cell types. This allows the stems cells to create important bodily organs like the heart, skin, lungs and others required for the condition needed to sustain life. In adults, these stem cells generate replacement cells for the units that are lost in the event of wear or tear, injury or other such matter; replacing the damaged tissue from bodily organs to sustain and maintain the health of the organism.
http://stemcells.nih.gov/info/basics/pages/basics1.aspx
Why is Therapeutic Cloning used?
Furthermore, the purpose of therapeutic cloning is not to create actual human clones, but to treat conditions and diseases that were once thought to be untreatable, like osteoporosis. This type of therapy is beneficial for the reason that the cells used are pluripotent, which essentially means that they may eventually become any type of cell except for the zygote, in which case would be considered a totipotent cell. The fact that this treatment uses the patient’s own DNA eliminates the risk of host cell rejection, which is one of the biggest problems in cases like organ donation. Therapeutic cloning may be paving the road for new treatments to come, since its applications in contemporary medicine are used to better understand the bigger benefits that this therapy may bring.
Above: Skin cells reprogrammed to other various cells.
http://www.wired.com/medtech/stemcells/news/2007/11/skin_cell
How is it completed?
As mentioned before, therapeutic cloning is the procedure of utilizing embryonic human cells, to create identical cells, for regenerative medicines used in treatment. In the “scientific world”, researchers entitle this procedure as somatic cell nuclear transfer (SCNT). For this procedure, researchers extract the nucleus from the egg, where the nucleus stores all the genetic information for any living subject. Then researches take a somatic cell, which is any type of cell that is not a gamete, and extract its nucleus from the cell. In human patient applications, the somatic cell would be extracted from the patient who requires a regenerative transplant to treat their specific health condition.
The nucleus that was extracted from the somatic cell, from the patient, is then inserted into an egg, after the due extraction of the egg’s nucleus. The egg, containing the genetic material, can now form into a cluster of cells known as a blastocyst (the result of the first mitotical division of the zygote). The blastocyst’s 2 cells have two layers (inner and outer), the inner layer contains a rich content of stem cells, that is then used to create embryonic stem cell lines. These cell lines are then infused into the patient where they are integrated into the tissue in treatment, causing the cells, from the lining, to develop into the damaged tissue for repair.
http://www.explorestemcells.co.uk/therapeuticcloning.html
While researching, we managed to find detailed diagrams, from a website called Scientific American, that explains the process in a cellular point of view:
1.
Eggs are coaxed to mature in a culture dish. Each has a remnant egg cell called the polar body and cumulus cells from the ovary clinging to it.
2.
While an egg is held still with a pipette, a needle is used to drill through the zona pellucida, removing a plug.
3.
After ejecting the zona plug, the needle is inserted back in the egg through the hole to withdraw and discard the polar body and the egg's genetic material.
4.
A cumulus cell from another egg is taken up into the needle. Cells called fibroblasts (or their nuclei) can also be used in this step.
5.
The cumulus cell is injected deep into the egg that has been stripped of its genetic material.
6.
The injected egg is exposed to a mixture of chemicals and growth factors designed to activate it to divide.
7.
After roughly 24 hours, the activated egg begins dividing. The cells contain genetic material only from the injected cumulus cell.
8.
By the fourth or fifth day, a hollow ball of roughly 100 cells has formed. It holds a clump of cells called the inner cell mass that contains stem cells.
9.
The blastocyst is broken open, and the inner cell mass is grown in a culture dish to yield stem cells.
10.
The stem cells, in turn, can be coaxed to grow into a variety of cells that might one day be injected into patients.
Images: JANA BRENNING
http://www.scientificamerican.com/article.cfm?id=therapeutic-cloning-how-i
Therapeutic Cloning Success Stories
1. 9-month-old Chloe Levine was diagnosed with right-side hemoplegic cerebral palsy, which affected all motor movements from this side of her body. The neurologist consulted for this case stated that the young Arizonian would have to endure almost 20 years worth of therapy, until the parents remembered they had stored her cord blood cells when she was born. This meant they could try a new experimental procedure to repair damaged brain tissue causing her problems. Only 2 months after her first infusion of stem cells she had already improved 50%.
http://www.cells4life.co.uk/why-store-stem-cells/stem-cell-case-studies/stem-cells-cure-diabetes-case-study
2. Another case involves the temporary relief of the symptoms of Diabetes type 1. In studies done with people just diagnosed with this disease, they compared a group they infused with blood cord stem cell while another group was given a placebo. The results showed that the group of participants that were given the infusion went on average 2 ½ years without the need of daily insulin injections. "Stem cell transplants 'have freed patients with type 1 diabetes of daily insulin injections” said The Daily Telegraph on the subject.
http://www.cells4life.co.uk/why-store-stem-cells/stem-cell-case-studies/cord-blood-stem-cells-reverse-girls-cerebral-palsy-case-
3. Studies are finding that ALS, or Lou Gherig’s Disease, a usually untreatable degenerative disease, can be managed by the usage of cord blood stem cells. This would help by developing factors that will preserve their remaining nerve cells. Although the studies available are only just correlational, they may be giving way to new investigations that may arise to provide with a permanent cure for this awful disease.
http://www.cells4life.co.uk/news-events/fatal-disease-als-may-be-treatable-stem-cells
Legal Aspects of Therapeutic Cloning
Due to the inconsistent in information that was found on the subject it is not clear whether therapeutic cloning is legal, or illegal for that matter, across the Unites States. Some sources stated that only limited states in the USA have permission to use stem cells for therapeutic cloning, not reproductive cloning. This however, does not account for the fact that the United States has no strict federal laws permitting or prohibiting the use of stem cells for research, as this would arise a debate with Constitutional rights, similar to the one for abortion and women rights. There are also places, like the United Kingdom, that although they ban the use for reproductive cloning, they do allow research for therapeutic reasons.
What is the controversy related to its use?
Although the health benefits if therapeutic cloning is apparent, the ethics of cloning is a very controversial issue. Therapeutic cloning, however, is much less controversial than reproductive cloning. This is because therapeutic cloning does not involve the destruction of a fertilized egg that could develop into a human being. However, therapeutic cloning does involve the destruction of an embryo, making some consider the act to be the termination of potential human life. Many people find the use of human eggs for research to involve a severe lack of respect to the sanctity of human life. Furthermore, some people believe that therapeutic cloning, or any cloning for that matter, tampers with the natural fabric of life and should be prohibited. For the most part, the disease and condition curing benefits of therapeutic cloning seem to outweigh the doubts and concerns that arise from it’s ethical factors.
Additional sources used:
http://www.ornl.gov/sci/techresources/Human_Genome/elsi/cloning.shtml
http://www.explorestemcells.co.uk/therapeuticcloning.html
http://www.scientificamerican.com/article.cfm?id=therapeutic-cloning-how-i
http://stemcells.nih.gov/info/basics/pages/basics1.aspx
http://www.cells4life.co.uk/why-store-stem-cells/stem-cell-case-studies/cord-blood-stem-cells-reverse-girls-cerebral-palsy-case-
What do you think?
Do you think therapeutic cloning is ethical?
